Family history of schizophrenia as a risk factor for axis I psychiatric conditions

People with first-degree relatives with schizophrenia are at an elevated risk of developing the disorder themselves. High rates of psychotic symptoms in non-psychotic disorders, high rates of comorbidity in psychotic disorders, and diversity of outcomes following psychosis-risk states together suggest that this vulnerability may be for psychiatric conditions in general, not limited to schizophrenia. In this study, data from the National Survey of American Life (NSAL) were used to examine the association between having a first-degree relative with schizophrenia and the lifetime development of a range of non-psychotic axis I psychiatric disorders using adjusted odds ratios. Having a relative with schizophrenia was associated with increased risk for most non-psychotic psychiatric conditions examined, including those expected to be associated with schizophrenia (affective, anxiety, and substance use disorders) and those not expected (bulimia, disorders of childhood onset), excluding respondents with lifetime psychotic symptoms and controlling for demographic factors. Family history of schizophrenia among this predominantly African-American and Afro-Caribbean sample appears to be a risk factor for a range of axis I diagnoses, supporting a continuous rather than categorical nature of psychiatric vulnerability. Future studies should examine whether these associations are due to genetic or environmental factors, or both.